Hi,
I am currently building out a new production environment. Our current prod env uses RHEL5.8 but I am thinking of building out a RHEL6 environment since a complete end-to-end testing will need to take place prior to go-live anyway. Plus it is an ideal time to upgrade the OS across the board.
My current prod will become the DR site.
I plan to gradually upgrade the DR & pprod after the new env go-live.
This leaves a scenario where the live prod will run RHEL6 while the pprod and DR will run RHEL5 (for a short period of time).
Question is this; if application testing on RHEL6 proves successful is it a bad idea to have pprod and DR running RHEL5 (if only for alimited period of time?).
The answer really depends on the features your current environment is using.
Some third-party applications (e.g. Oracle, Teradata, Siebel, PeopleSoft, etc) are "certified" to run on RHEL 5.x but not on 6.x so if you are using their official support it would be best to comply with their specifications in order to avoid a negative response when you *really* need vendor assistance.
You should also evaluate the current features your environment is using: Does it heavily rely on NFS and/or virtualization? These two are some of the topics that have changed the most in RHEL6 (compared to RHEL5) and might need some major adjustments during a migration.
IMO, it would be reasonable for a development environment or even UAT but I wouldn't mix different OS versions for prod environment unless it's extremely necessary or for a very short period of time (throughout the migration process, for example).
